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Soft Bodies: btCompoundShapes interaction and raycast
Posted: Sun Apr 20, 2008 9:14 am
by Flix
I don't know if the "Soft Body" part of Bullet is complete or not (BTW: many compliments to its developer/s, the demo looks impressive to me). Anyway I'd like to know:
1) btCompoundShapes don't seem to interact with soft bodies at all according to my (newbie) experiments with a cloth patch. Is this correct ?
2) Is it (or will it) be possible to ray cast to detect soft bodies ?
Thank you in advance for your answers and for the development of Bullet.
Flix.
Re: Soft Bodies: btCompoundShapes interaction and raycast
Posted: Sun Apr 20, 2008 3:53 pm
by Erwin Coumans
btCompoundShape is easy to get working, and has already been fixed in Subversion:
Replace the getCollisionAlgorithm method in bullet-2.68\src\BulletSoftBody\btSoftBodyRigidBodyCollisionConfiguration.cpp by:
Code: Select all
///creation of soft-soft and soft-rigid, and otherwise fallback to base class implementation
btCollisionAlgorithmCreateFunc* btSoftBodyRigidBodyCollisionConfiguration::getCollisionAlgorithmCreateFunc(int proxyType0,int proxyType1)
{
///try to handle the softbody interactions first
if ((proxyType0 == SOFTBODY_SHAPE_PROXYTYPE ) && (proxyType1==SOFTBODY_SHAPE_PROXYTYPE))
{
return m_softSoftCreateFunc;
}
///softbody versus convex
if (proxyType0 == SOFTBODY_SHAPE_PROXYTYPE && btBroadphaseProxy::isConvex(proxyType1))
{
return m_softRigidCreateFunc;
}
///convex versus soft body
if (btBroadphaseProxy::isConvex(proxyType0) && proxyType1 == SOFTBODY_SHAPE_PROXYTYPE )
{
return m_swappedSoftRigidCreateFunc;
}
///fallback to the regular rigid collision shape
return btDefaultCollisionConfiguration::getCollisionAlgorithmCreateFunc(proxyType0,proxyType1);
}
Ray casting versus soft body has been implemented (press comma in the tests), but not hooked up to the btCollisionWorld::rayTest yet.
Those issues and also soft body versus concave mesh will be fixed in 2.69 (see also
http://www.bulletphysics.com/Bullet/php ... 041&p=8004)
You can check out a very early prototype of soft body versus concave triangle mesh (btBvhTriangleMeshShape) here:
http://bulletphysics.com/ftp/pub/test/p ... dyDemo.zip
Hope this helps,
Erwin
Re: Soft Bodies: btCompoundShapes interaction and raycast
Posted: Tue Apr 22, 2008 12:50 pm
by Flix
Wonderful! Thank you.
Flix